Floating platform

ABSTRACT

A floating platform having a plurality of float units which are interconnected together in end to end relation with their top surface portions being substantially flush with each other, each of the interconnected units having a predetermined buoyancy which is sufficient to float the platform in a flotation medium, such as water, wherein at least two of the units have a different relative predetermined buoyancy with respect to each other and the flotation medium prior to external loading thereof. The platform is arched along at least a predetermined portion of its length prior to external loading thereof. The arched portion may be either convex or concave or a combination thereof, depending on the relative buoyancy of the interconnected units and the intended use of the platform. Furthermore, if desired, the buoyancy of the various units may be chosen so as to float the platform below the surface of the flotation medium or to float the platform with at least a portion thereof above the surface of the flotation medium. The units are preferably interconnected by means of tension elements, such as rods or cables which are posttensioned during the assembly of the platform. A floating platform may also be formed from a plurality of such float units which are interconnected together in side to side relation with their top surface portions being substantially flush with each other, in addition to having the units interconnected together in end to end relation. The relative buoyancies of the side to side interconnected units may also be different so as to provide a side to side arched portion as well as an end to end arched portion for the complete structure, or any combination thereof. The units are preferably interconnected in side to side relation by transverse tension elements in the same manner as the longitudinal end to end interconnections.

United States Patent [191 Sheil FLOATING PLATFORM [76] Inventor: John E. Sheil, 196 Black Smith Rd.,

Levittown, NY. 11756 [22] Filed: Dec. 28, 1971 [21] Appl. No.: 213,102

[52] US. Cl. 114/0.5 F

[51] Int. Cl B631) 35/00 [58] Field of Search ll4/0.5 F, 43.5, 77; 61/5, 61/1 F; 9/8 P; 14/27, 28

[56] References Cited UNITED STATES PATENTS 3,276,209 10/1966 Mosdell 61/5 3,546,773 12/1970 Gerstin ll4/43. 5

3,468,393 9/1969 Harrison 114/77 R 2,107,886 2/1938 Creed l14/43.5

3,022,759 2/1962 McCall ll4/.5 F

Primary Examiner-George E. A. Halvosa Attorney, Agent, or Firm-Myron Cohen et al.

[ 5 7 ABSTRACT A floating platform having a plurality of float units which are interconnected together in end to end relation with their top surface portions being substantially flush with each other, each of the interconnected units having a predetermined buoyancy which is sufficient to float the platform in a flotation medium, such as water, wherein at least two of the units have a differ- 1 Jan. 29, 1974 ent relative predetermined buoyancy with respect to each other and the flotation medium prior to external loading thereof. The platform is arched along at least a predetermined portion of its length prior to external loading thereof. The arched portion may be either convex or concave or a combination thereof, depending on the relative buoyancy of the interconnected units and the intended use of the platform. Furthermore, if desired, the buoyancy of the various units may be chosen so as to float the platform below the surface of the flotation medium or to float the plat form with at least a portion thereof above the surface of the flotation medium. The units are preferably interconnected by means of tension elements, such as rods or cables which are post-tensioned during the assembly of the platform. A floating platform may also be formed from a plurality of such float units which are interconnected together in side to side relation with their top surface portions being substantially flush with each other, in addition to having the units interconnected together in end to end relation. The relative buoyancies of the side to side interconnected units may also be different so as to provide a side to side arched portion as well as an end to end arched portion for the complete structure, or any combination thereof. The units are preferably interconnected in side to side relation by transverse tension elements in the same manner as the longitudinal end toend interconnections.

15 Claims, 12 Drawing Figures PATENTED 3.788.254

SHEET 2 0F 3 33,, FIG. 9.

FLOATING PLATFORM BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to structural floating platforms comprised of interconnected modular units.

DESCRIPTION OF THE PRIOR ART To date there are no satisfactory structural floating platforms for use with concentrated dead loads, such as buildings or structures, with concentrated live loads such as a helicopter landing platforms, or with centrally or axially aligned loads such as roadways and aircraft runways. This problem becomes particularly acute with respect to the construction of such platforms from modular units, which is the only practical solution to providing a large structural platform such as for use as a roadway or runway. In an attempt to overcome this problem, floating platforms have been constructed of individual units capable of sliding side by side in order to make the necessary vertical adjustment when loads of varying magnitude are applied to the platform. The existence of this condition or capability weakens the integrity of the platform as a whole and is thus unsatisfactory. Another prior art attempt at solving this problem has involved the use of modular units of equal size and buoyancy interconnected to form the platform with no vertical slippage permitted between adjacent units. However, when a concentrated load is applied to such a platform, the load will cause the platform to deflect at the point of impact of the load, such a platform having low resistance to impact loads. This is unsatisfactory when the platform is required to resist concentrated live loads, such as when utilized as a helicopter landing platform, or when the platform is required to resist centrally or axially aligned loads, such as when the platform is utilized as a roadway or aircraft runway, in which instance concentrated live loads may also be applied.

Furthermore, such prior art platforms consisting of a plurality of interconnected floats of uniform buoyancy are not satisfactory when required to resist concentrated dead loads of varying magnitude along the length of the platform, such as when a building or structure is erected on the platform. In such an instance the platform would permanently deflect at the point of concentrated dead load rather than remaining level. This is unsatisfactory. Accordingly, no satisfactory prior art structural floating platforms composed of a plurality of interconnected modular units are presently available.

The present invention overcomes these disadvantages of the prior art.

SUMMARY OF THE INVENTION A floating platform includes a plurality of float units which are interconnected together in end to end relation with their top surface portions being substantially flush with each other, each of the interconnected units having a predetermined buoyancy which is sufficient to float the platform in the desired flotation medium, such as water. Preferably, at least two of the units have a different relative predetermined buoyancy with respect to each other and the flotation medium prior to external loading thereof whereby the platform is arched along at least a portion of its length prior to external loading thereof. The arched portion of the platform may be either convex or concave or a combination thereof, depending on the intended use; When the arched portion is convex with respect to the surface of the flotation medium, the resistance to impact loads of the platform is relatively high. In addition, the arching of the platform may provide a camber in the direction of anticipated applied load which camber is preferably a predetermined amount depending on the amount of applied dead load, which is normally known, so that when the predetermined concentrated dead load is applied to the platform at the point of camber, the platform will become level, as desired, rather than deflecting so as to be concave at this point, which would be undesirable. In addition, the relative buoyancy of the various units may be adjusted so as to have the platform float beneath the surface of the flotation medium such as when the platform is desired to be used as a drydock.

Preferably, the various units of the platform are interconnected by tension elements, such as cables or rods, which are post-tensioned during the assembly of the platform. In addition, resilient compression pads are preferably provided between adjacent float units for distributing the compressive load between the units and compensating for any non-uniformities in the end wall of the units. The units may be connected in subassemblies of multiple units interconnected by tension elements which are joined to another subassembly of units interconnected by tension elements by means of structural tubing interconnecting the appropriate tension elements. In addition, if desired, several units may be interconnected by means of a tension rod which is tensioned at the end of the rod by means of a nut. In either event, a substantially continuous tension element is provided for interconnecting the units comprising the platform.

The relative variations in buoyancy of respective units may be provided by providing units of varying depth or size or by utilizing uniform size units of the dimension of the largest required and then adding ballast to appropriate float units to adjust their buoyancy to the desired amount. Furthermore, the floats may be a bottomless box, a hollow box with a bottom, or a hollow box with or without a bottom whose interior is filled with foam or some other medium to provide buoyancy. In addition, the floats may also be constructed of a substantially solid buoyant material, although this is not the preferred arrangement.

A floating platform structure may also be formed from a plurality of such float units which are interconnected together in side to side relation with their top surface portions being substantially flush with each other, in addition to having the units interconnected together in end to end relation. The relative buoyancies of the side to side interconnected units may also be different so as to provide a side to side arched portion as well as an end to end arched portion for the complete structure, or any combination thereof. The units are preferably interconnected in side to side relation by transverse tension elements in the same manner as the longitudinal end to end interconnections.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a diagrammatic illustration of an artificially suspended platform constructed in accordance with the present invention;

FIG. 2 is a diagrammatic illustration of the preferred embodiment of the present invention showing a convex arched platform;

FIG. 3 is a diagrammatic illustration of the preferred embodiment of the present invention showing the platform of FIG. 2 with an illustrative concentrated dead load thereon;

FIG. 4 is a diagrammatic illustration of a modification of the embodiment shown in FIG. 2;

FIG. 5 is a diagrammatic illustration of an alternative embodiment of the present invention;

FIG. 6 is a diagrammatic illustration of still another alternative embodiment of the present invention showing a concave arch for the platform;

FIG. 7 is a diagrammatic illustration of yet another alternative embodiment of the present invention showin g both a convex arch together with a concave arch for the platform;

FIG. 8 is a partial sectional perspective view of the preferred embodiment of the platform of the present invention;

FIG. 9 is a fragmentary plan view of the preferred embodiment of the present invention, similar to FIG. 8 but illustrating a different manner of coupling the tension element means together;

FIG. 10 is a diagrammatic illustration of another modification of the embodiment shown in FIG. 2;

FIG. 11 is a partial sectional perspective view, similar to FIG. 8, of an alternative embodiment of the platform of the present invention showing a plurality of units interconnected in side to side relation as well as end to end relation; and

FIG. 12 is a partial sectional perspective end view of the embodiment shown in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, and especially to FIGS. 1 and 8 thereof, the preferred embodiment of the floating platform of the present invention, generally referred to by the reference numeral 20, shall be described. The floating platform 20 of the present invention preferably is formed from a plurality of modular float units 22. By way of example, and not by way of limitation, the platform 20 shown in FIG. 1 comprises eleven such float units 22a, 22b, 22c, 22d, 22e, 22f, 22g, 22h, 22j, 22k and 22m. Preferably, each of these float units 22a through 22m, inclusive, is identical in construction, the only variation between particular units, as will be described in greater detail hereinafter, preferably being in the relative buoyancy of the respective unit with respect to the flotation medium for the floating platform 20. For purposes of explanation, we shall assume that the flotation medium is water, although the present invention may be utilized in any other desired flotation medium, such as a viscous fluid.

The floating platform 20 is preferably constructed of at least two modular portions having a different relative predetermined buoyancy with respect to each other and the flotation medium prior to any external loading of the platform 20. In the example shown in FIG. 1, the platform 20 is shown as a symmetrical configuration of various areas of different relative buoyancy. The end areas 24 and 26, in the example shown, are preferably arranged to have the lowest relative buoyancy with respect to the flotation medium and, since as was previously mentioned, the configuration shown in FIG. 1 represents a symmetrical configuration, these areas are of equal buoyancy. As shown in this example, both areas 24 and 26 are formed from two modular flotation units 22a and 22b for area 24, and 22k and 22m for area 26, by way of example and not limitation. The platform illustrated in FIG. 1 also includes buoyant areas 28 and 30 which, in the illustrative symmetrical configuration shown in FIG. 1, are each of equal buoyancy. Once again, by way of example and not limitation, buoyant areas 28 and 30 are each illustratively shown as being composed of two modular flotation units, 22c and 22d for area 28, and 22h and 22j for area 30. Lastly, the center portion of the illustrative symmetrical configuration for platform 20, buoyant area 32, is illustratively shown, by way of example and not limitation, as being formed of three identical modular units 22e, 22f and 22g.

In the example shown in FIG. 1, the overall dimensions of the respective modular units 22a through 22m inclusive, are substantially identical except for the relative height or depth of the unit. Thus, the cross sectional areas of each of the units are substantially identical and the variations in buoyancy are due to the variations in the height of the unit. Thus, units 22a, 22b, 22k

and 22m are all preferably of substantially identical size, including height, and are thus, preferably, of equal buoyancy. Similarly, units 22c, 22d, 22h and 22j are all, preferably, of substantially identical size, including height, and are all of equal buoyancy; however, the relative height and, thus, the relative volume of the respective modular units comprising areas 28 and 30 is greater than that for areas 24 and 26 and, thus, the buoyancy of units 22c, 22d, 22h and 22j is greater than the respective buoyancy of units 22a, 22b, 22k and 22m. Lastly, the respective heights and, thus, the respective volumes of units 22e, 22f and 22g comprising area 32 are each substantially equal to each other and greater than the respective heights and thus volume of the units comprising both areas 24 and 26, and 28 and 30. Thus, area 32 has a greater buoyancy then the other areas. If desired, the differences in relative buoyancy need not be obtained by variations in the volume of the respective modular units but rather may be obtained in any other conventional manner such as by utilizing modular units which are all of the same overall dimensions, including interior volume, of the largest unit required and then adding ballast to the appropriate units or material to the bottoms thereof to adjust their relative buoyancy to produce the appropriate variations in buoyancy, the deeper units occurring on the extremeties and the shallower ones in the center in the latter case.

Referring now to FIG. 8, the individual modular units 22 are each preferably composed of hollow box configurations. By use of the term box it is meant to include configurations both with and without an integrally formed bottom portion although, as shown and preferred, the modular units are preferably formed with an integral bottom portion or bottom slab. In addition, if desired, configurations without such a bottom, such as those configurations normally termed inverted bathtubs" in the art may be utilized. Furthermore, if desired, the interior of the hollow unit may be filled with air or may be filled with a buoyant substance such as a foam-like substance available under the trade name Styrofoam." In addition, if desired, the modular unit may be constructed of a substantially solid mass of buoyant material, although such a construction is not preferred.

As shown and preferred in FIG. 8, the modular unit 22 is preferably a hollow enclosed box, having a bottom portion or slab 34, a pair of upstanding end wall portions 36 and 38, a pair of upstanding sidewall portions 40 and 42 (not shown) and a top wall or slab portion 44. As shown and preferred, the hollow enclosed box is preferably formed of concrete, although any other structural material such as wood, steel, fiberglass, or plastic, by way of example, may be utilized. Preferably, the top wall or slab portion 44 of the hollow enclosed box is of sufficient thickness to withstand expected external loading on the floating platform structure in the area of the particular modular float unit.

As will be explained in greater detail hereinafter, this loading may be a dynamic impact load or may be a static dead load applied to the floating platform structure 20, such as by a building. When the modular unit 22 is constructed with a bottom wall portion 34, as shown and preferred, this bottom wall or slab is preferably of sufficient thickness to withstand hydrostatic pressures caused by the condition of submergence of the particular modular unit portion of the floating platform 20. Under normal conditions, the thickness of the top wall or slab portion 44 is considerably greater than that of the bottom wall or slab portion 34 due to the relative differences in the applied forces. It should be noted, however, that the relative buoyancy of a given unit 22 may be adjusted by thickening the bottom slab 34 which, correspondingly, places the added weight of the unit in a position which lowers the center of gravity thereof and, therefore, aids in the stability of the unit. The end wall portions 36 and 38, as shown and preferred, are each of non-uniform thickness, the end walls 36 and 38 preferably being thicker above the flotation line or water line of the buoyant box, which is preferably concrete in the example shown, than below this line. The purpose for this is that a thicker end wall is normally required to support the top wall or slab portion 44 and to withstand the external forces applied thereto while a thinner portion is required for the lower portions of the end walls 36 and 38 as this portion of the end walls need only be sufficient to withstand the forces due to the condition of submergence which forces are normally considerably less than the external loading applied to the platform 20. If desired, however, the end walls may be of uniform thickness, the thickness being great enough to withstand the maximum applied force to the modular unit 22, whether it be to the top wall portion 44 or the bottom wall portion 34, as well as being sufficient to support the top wall portion 44. However, this is less efficient than providing a nonuniform thickness for the end wall portions 36 and 38. The non-uniform thickness for the end wall portions 36 and 38 is shown in FIG. 8 as being provided in a steplike fashion although, if desired, this non-uniform thickness may be provided by a more gradually tapered arrangement. The arrangement for the end wall portions 36 and 38 preferably likewise applies to the arrangement, that is, configuration, of the side wall portions 40 and 42, which has been omitted for purposes of clarity. Although, by way of example, the end wall portions 36 and 38 are preferably shown and preferred as being thickened. internally, if desired these walls could be thickened externally or both internally and externally to provide for the requisite desired deflection of an arched platform structure. As will be explained in greater detail hereinafter with reference to FIGS. 11 and 12, the side wall portions as well as the end wall portions may be similarly thickened.

As shown and preferred in FIG. 8, the various modular units 22 comprising the floating platform 20 are preferably interconnected together in end to end relation solely by means of a pair of spaced apart tension rods 50 and 52 or, if desired, tension cables, although, if desired, more than one pair of tension elements may be utilized. Preferably, internal chaseways 54 and 56, respectively, are provided in the end wall portions 36 and 38 of the various modular units 22a through 22m, inclusive, preferably in the thickened portions thereof, comprising the floating platform 20. If desired, the chaseways 54 and 56 may be provided by a hollow sleeve, such as a polyvinyl chloride sleeve, a steel pipe sleeve or an aluminum pipe sleeve, therein with the respective tension rods 50 or 52 passing therethrough. As shown and preferred, the modular units 22a through 22m, inclusive, are interconnected via the tension rods 50 and 52, which are preferably in the same horizontal plane with respect to each other, so as to provide a flush top surface for the platform from the various top surface portions 44 of the modular units 22a through 22m, inclusive. In order to accomplish this, in constructing the modular units 22, the internal chaseways 54 and 56 are preferably located in the end wall portions 36 and 38 in the same position. Thus, the modular units 22 may be interconnected with the chaseways aligned in the horizontal plane so as to provide a flush top surface to be utilized as the structural platform 20. If desired, of course, the top surface of the overall platform as well as of the individual modular units need not be integrally formed therewith or therefrom and a separate top surface may be mounted on the assembled units or utilized to complete the unit structure.

Preferably the tension rods 50 and 52 are located in the floating platform structure 20 such that they always occur in the upper plane of each modular unit 22 and in the same relative location with reference to the top surface, no matter how the overall dimension of the units is varied to provide the different relative buoyancies. The tension rods 50 and 52, or cables, may each be formed of a continuous element or, as is more practical, may be formed of several elements linked together either by a coupling nut or structural tubing. The use of structural tubing is illustrated in FIG. 9 and the use of a coupling nut is illustrated in FIG. 8.

In addition, as shown and preferred, resilient bearing pads 60a, 60b, 60c and 60d (not shown) are provided between end to end connected adjacent modular units 22 comprising the floating platform. These pads 600 through 60d, inclusive, which may be formed of any resilient material, such as neoprene rubber, serve to compensate for deflections created in the assembled floating platform 20, distribute the load (pressure contact between the units) on the given end wall surface area and compensate for any non-uniformities in the end wall portion. These pads are preferably placed where compression will occur and, thus, are always preferably utilized at the location of the tension rods 50 and 52 between the adjacent end wall portions at these points. Preferably, the tension rods 50 and 52 pass through an aperture in the appropriate bearing pad 60, such as through the center thereof, similar to the arrangement described in US. Pat. No. 3,091,203. The respective apertures are of slightly greater transverse cross sectional area than that of the tension element passing therethrough and are preferably axially aligned with the respective chaseway. In addition, a bearing pad or pads are provided near the bottom wall portion of one of the adjacent modular units so that the bottom portion of the end wall portion does not bear directly against the adjacent modular units. Thus, in the example shown, by way of example and not limitation, four resilient bearing pads are provided for each modular unit, two in a horizontal plane close to the top surface 44 and two in a horizontal plane close to the bottom surface 34 of the particular modular unit 22. In addition to the use of resilient bearing pads 60, bearing plates or washers 62a and 62b (FIG. 8) are preferably utilized in conjunction with the bearing pads 60a and 60b, respectively, in order to distribute the compressive effect of the nut from which the tension is applied, 61a and 61b, respectively, across the respective bearing pads 60a and 60b, the thickness of the bearing plates 62a and 62b being dependent on the tensile stress of the appropriate rod nut 61a and 61b or the cable clamp (not shown).

The arrangement with respect to the use of structural tubing 63a and 63b (FIG. 9) is similar in that a bearing pad is utilized between the end portions of the structural tubing and the abutting end wall portions of the float units 22 whose tension rods are interconnected thereby.

Referring now to FIG. 2, if the relative buoyancies of the various modular units 22 comprising the floating platform are adjusted so as to-provide a symmetrical configuration, such as illustrated in FIG. 1, wherein the extremities are the least buoyant portions of the platform structure 20 and the center thereof is the most buoyant portion, then when this platform structure 20 is assembled in the water or flotation medium and all external loading is removed therefrom, a platform 20 which is arched in a convex fashion, such as illustrated in FIG. 2, will be provided. Such a platform 20 has a high resistance to impact loading. The convexity of the platform 20 in the embodiment shown in FIG. 2 is created by the dead load of the system, that is the load of the system prior to any external loading thereof, overcoming the artificially created top plane surface of the structure. Thus, as was previously mentioned, the arching of the platform creates locations within the platfrom structure 20 where the platform is suspended above the plane of its theoretical at rest position, thereby providing additional built-in potential of the platform to resist impact loads. Thus, the configuration illustrated in FIG. 2 is useful where resistance to such live loads is desired, such as in a roadway or aircraft runway or helicopter landing platform. As will become apparent to one of ordinary skill in the art, innumerable possibilities are provided with such a structure. Thus, for example, as shown in FIG. 4, the buoyancy of the extremities of the platform 20, which is a platform similar to the platform of FIG. 2, may have the relative buoyancies thereof lowered, such as by the addition of ballast, so that the extremity portions, such as 24 and 26, of the floating platform 20 are below the surface of the water or flotation medium, such as for use as an amphibious landing platform. In addition, the arched or convex surface of the platform naturally provides drainage run-off, which is desirable in any large 'area floating platform. I As shown in FIG. 3, a convex platform similar to the symmetrical configuration shown in FIG. 2 may be provided with a camber in the direction of anticipated applied dead load, the camber being a predetermined amount dependent on the known dead load to be resisted. Thus, when a dead load, such as a building structure 100, is mounted on such a platform 20, the platform will become flat along its top surface due to the balancing of the buoyant force causing the camber, which in this instance is a convex arch, by the dead load of the building structure mounted thereon. Thus, the platform 20 is prevented from being undesirably concave at the point of application of the known dead load.

In addition, by way of example, as shown in FIG. 5, the floating platform 20a may also be constructed in an unsymmetrical configuration such as where the buoyancy of one extremity is less than the buoyancy of the outer extremity. This may be accomplished by interconnecting various modular units whose relative predetermined buoyancies are such that the units at one extremity have lower buoyancy than the units at the other extremity. Such a platform could be utilized as a wave suppressor for protecting harbor areas. Once again, the inclined arched surface also aids in providing drainage runoff.

The embodiment shown in FIG. 6 illustrates the same basic principle of the present invention wherein the floating platform 20b is constructed of modular units in which at least two of the units have a different predetermined relative buoyancy; however, the arched platform in FIG. 6 is shown as providing a concave top surface. The platform structure 20b shown by way of example in FIG. 6, is a symmetrical configuration and the concavity is provided for the structure 20b by interconnecting modular units at the extremities which are more buoyant than the modular units provided at the center of the platform 20. Such a concave platform may be utilized for many uses such as a floating swimming pool, catch basin, etc.

Furthermore, if desired, a floating platform 20c constructedin accordance with the present invention may have both concave portions and convex top surface portions such as may be required for complex loading configurations or to handle drainage properly. Such an arrangement is illustrated in FIG. 7 wherein the floating platform 200 may be utilized as an airplane runway having a shallow water bath restraint at the end thereof for overshoot of the runway. In order to construct such a complex configuration, all that is required is that the modular units at the point of convexity have a greater buoyancy than the adjacent modular units and the modular units at the point of concavity have a lower buoyancy than the adjacent modular units. Such variations in buoyancy, as was previously mentioned, may be accomplished either by means of additional ballast being added to the appropriate modular units or by changing the overall dimensions of the appropriate modular units.

In addition, as shown in FIG. 10, the buoyancy of the various modular units and, hence, the overall buoyancy of the assembled floating platform 20 may be adjusted such that the floating platform floats or is suspended beneath the top surface of the flotation medium or water such as for use as a drydock. Accordingly, by the use of the term float or buoyant is meant the suspension of the platform in a fixed position in the flotation medium.

While the principles of the invention have been described above with reference to a floating platform structure constructed in an end to end linear or longitudinal direction, it will become apparent that these principles are equally applicable to a floating platform structure which is constructed in both a side to side radial or transverse direction as well as an end to end longitudinal direction, such as illustrated in FIGS. 11 and 12. By way of illustration and not limitation, a pair of side to side interconnected duplicate assemblies of flotation units 22a] through 22ml, inclusive, and 22az through 22mz, inclusive, is shown, which units are correspondingly identical to those previously described above and which, preferably, have their respective top wall portions 44, side wall portions 40 and 42, and end wall portions 36 and 38 aligned in the assembled structure, with the corresponding top wall portions being substantially flush in both the longitudinal or end to end direction and the transverse or side to side direction. The flotation unit assemblies 22a] through 22ml, inclusive, and 22az through 22mz, inclusive, are preferably interconnected in end to end relation as described above with reference to the exemplary single unit wide floating platform structure 22a through 22m, inclusive. Preferably, the interconnection of the duplicate assemblies of the corresponding flotation units 22a] through 22ml, inclusive, and 22az through 22mz, inclusive, in side to side relation, that is side wall portion 40 of a corresponding adjacent unit 22a! through 22ml, inclusive, being interconnected through side wall portion 42 of the corresponding transversely adjacent unit 22az through 22mz, inclusive, is accomplished in a similar manner to that previously described above with reference to the end to end interconnection of the flotation units.

The side wall portion 40 and 42 are preferably thickened in the same manner and for essentially the same purpose as end wall portions 36 and 38. Transverse internal chaseways 100 and 102, similar in structure and purpose to chaseways 54 and 56 are preferably provided in the side wall portions 40 and 42 preferably in the thickened portions thereof, and preferably in the same horizontal plane with respect to each other but preferably slightly above or below the horizontal plane of the longitudinal chaseways 54 and 56 located in the end wall portions 36 and 38 so as not to intersect, the transverse chaseways 100 and 102 preferably being parallel to each other and normal to chaseways 54 and 56. If desired, the transverse chaseways 100 and 102 may be provided with a hollow sleeve, such as polyvinyl chloride, a steel pipe sleeve or an aluminum pipe sleeve, with the respective tension rods 104 and 106 passing therethrough. The corresponding flotation units 22a! through 22ml, inclusive, and 22az through 22mz, inclusive are preferably interconnected together in side to side relation in similar fashion solely by means of a pair of spaced apart tension rods 104 and 106 similar to tension rods 50 and 52, or, if desired, tension cables, the respective transverse tension rods 104 and 106 preferably passing through chaseways 100 and 102 slightly below (as shown in FIGS. 11 and 12) or above longitudinal tension rods 50 and 52. The tension rods 104 and 106 are preferably located in the floating platform structure such that they always occur in the upper plane of each modular unit and in the same relative location with reference to the top surface no matter how the overall dimensions of the units is varied to provide the different relative buoyancies. The interconnection of the units in both side to side and end to end relation in the manner described above preferably provide a flush top surface for the assembled platform structure in both the longitudinal and the transverse directions from the various top surface portions 44 of the modular units 2201 through 22ml, inclusive, and 22az through 22mz, inclusive.

Preferably, resilient bearing pads 1080 through 108d (not shown) identical with pads 60a, 60b, 60c and 60d are provided between side to side connected adjacent modular units 22 comprising the floating platform, these pads similarly serving, in this instance, to compensate for deflections created in the assembled platform, distribute the load (pressure contact between the units) on the given side wall surface area and compensate for any non-uniformities in the side wall portion. Similarly, these pads 108a through 108d (not shown) are preferably placed where compression will occur and, thus, are always preferably utilized at the location of the transverse tension rods and 102 between the adjacent side wall portions at the points, the tension rods 100 and 102 preferably passing through an aperture in the appropriate bearing pad 108, such as through the center thereof, similar to the arrangement previously described with reference to bearing pads 60. Also, similarly, bearing plates or washers 110a and 110b, which are preferably identical in structure and purpose to washers 62a and 62b, are preferably utilized in conjunction with the bearing pads 108a and 10812, respectively, in order to distribute the compressive effect of the nut 112a and 112b, respectively, from which the tension is applied, across the respective bearing pads 108a and 108b, the thickness of the bearing plates 110a and 110b being dependent on the tensile stress on the appropriate rod nut 112a and 112b or the cable clamp (not shown).

It will, of course, become apparent that the relative buoyancies of the respective modular units 22a] through 22ml, inclusive, and 22az through 22mz, inclusive, may be varied so as to provide a platform which is arched either side to side, end to end, or both simultaneously, in whole or in part, convex, concave or a combination thereof, depending on the desired use of the platform. The variations in relative buoyancies are preferably accomplished in any of the manners previously discussed above with reference to the single unit wide embodiment. While only a two unit wide platform has been illustrated by way of example, it will become readily apparent tha floating platforms of any desired width, length and configuration, including arching thereof, may be constructed in accordance with the present invention, such as multiple unit width platforms of the type discussed with reference to FIGS. 1 through 10.

The above illustrated configurations of a floating platform structure are merely provided by way of example and numerous other configurations will occur to one of ordinary skill in the art.

It should be noted that in constructing the floating platform of the present invention, if desired, the platform may be assembled in the water from the various modular units with the modular units being nonuniformly loaded during construction so as to provide a flat top surface for the platform during construction for ease in inserting the tension rods or cables through the chaseways. Thereafter, the tension rods or cables may be post-tensioned in a conventional manner, such as by tightening the nuts on the rod with a torque wrench or by adjusting the cable clamps if cables are utilized, to the desired degree of tension. Thereafter, the additional non-uniform external loading utilized during the construction may be removed and the platform will assume the desired shape provided by the different relative predetermined buoyancies of the modular units forming the platform.

It should also be noted that the term thickening as used throughout the specification and claims is meant to include built up or strengthened so as to be equally applicable when the float unit is formed of any structural material such as concrete, plastic, wood, steel or aluminum.

It is to be understood that the above described embodiments of the invention are merely illustrative of the principles thereof and that numerous modifications and embodiments of the invention may be derived within the spirit and scope thereof.

What is claimed is:

1. A floating platform comprising: a plurality of float units, each of said units having at least a substantially planar top surface portion and a pair of substantially upright opposed end wall portions; and post-tensioning means for interconnecting said plurality of float units together in end to end relation with said substantially planar top surface portions being substantially flush with each other, said post-tensioning means extending substantially continuously through said plurality of float units and including means for maintaining a predetermined tension for said post-tensioning means for holding said float units together with a predetermined degree of pressure contact therebetween, said platform having a top surface, said platform top surface having a configuration comprising said interconnected plurality of float unit top surface portions, each of said interconnected units having a predetermined mass upon which a buoyancy associated with a floatation medium for said units is sufficient to float said platform in said floating medium, at least two of said float units having a different relative predetermined mass with respect to each other and the floatation medium prior to external loading thereof, said post-tensioning means interconnecting said plurality of float units together with said pressure contact therebetween, at least said two interconnected float unit top surface portions providing an arched portion in said platform top surface configura' tion for said platform in said floatation medium, said arched portion being along at least a predetermined portion of said platform top surface prior to external loading thereof.

2. A floating platform in accordance with claim 1 wherein the mass of said interconnected units is sufficie'nt to float at least a part of said arched portion of said platform above the surface of said flotation medium.

3. A floating platform in accordance with claim 1 wherein said plurality of float units includes at least one other float unit having a predetermined mass prior to external loading thereof which is substantially the same as the predetermined mass of one of said two units, said post-tensioning means interconnecting said one other unit and said two units in a substantially symmetrical arrangement in accordance with the relative masses of said units, said one other unit and said two units providing a substantially symmetrical arched portion in said platform top surface configuration along at least a predetermined portion-of said platform top surface prior to external loading thereof.

4. A floating platform in accordance with claim 1 wherein each of said end wall portions includes at least one tension element receiving passageway therein, each of said passageways being axially aligned and opening on said opposed ends of said units at a level below said float unit top surface portion but in the upper portion of the plane of said end wall portion; and said post tensioning interconnection means includes tension element means extending through said axially aligned passageways.

5. A floating platform in accordance with claim 4 wherein said tension maintaining means includes means for maintaining a predetermined tension on said tension element means for holding said float units together with said predetermined degree of pressure contact therebetween.

6. A floating platform in accordance with claim 5 wherein a resilient compression pad is disposed on said end wall portion between adjacent float units, said pad having an aperture therethrough of slightly greater transverse cross-sectional area than the transverse cross-sectional area of said tensionelement means, said aperture being axially aligned with said end wall passageway opening, said tension element means extending through said aperture, said pad being longitudinally compressed to deform said pad and distribute the pressure contact load between adjacent units when a predetermined tension is maintained on said tension element means for holding said float units together with said predetermined degree of pressure contact therebetween.

7. A floating platform in accordance with claim 5 wherein a resilient compression pad is disposed on an end wall portion of each of said float units, said pad having an aperture therethrough of slightly greater transverse cross-sectional area than the transverse cross-sectional area of said tension element means, said aperture being axially aligned with said end wall passageway opening, said tension element means extending through said aperture, said pad being longitudinally compressed to deform said pad and distribute the pressure contact load on the respective unit when a predetermined tension is maintained on said tension element means for holding said float units together with said predetermined degree of pressure contact therebetween.

8. A floating platform in accordance with claim 1 wherein each of said units comprises a hollow concrete box having a thickened top wall capable of withstanding a predetermined external loading of said platform, and said end wall portions are each of non-uniform thickness, said end walls being thicker above flotation line of said buoyant concrete box than below said line.

9. A floating platform in accordance with claim 1 wherein each of said units comprises a hollow concrete box.

10. A floating platform in accordance with claim 1 wherein each of said float units comprises a hollow box, the interior of at least one of said units containing a predetermined quantity of ballast therein for providing said predetermined mass for said unit, the mass varying in accordance with variations in quantity of ballast.

11. A floating platform in accordance with claim 1 wherein each of said units further includes a pair of substantially upright opposed side wall portions, said post-tensioning interconnecting means including means for interconnecting at least a portion of said plurality of float units together in side to side relation and at least a portion of said plurality of float units together in end to end relation with said top surface portions being substantially flush with each other.

12. A floating platform in accordance with claim 11 wherein at least two of said side to side interconnected units have a different relative predetermined mass with respect to each other and the flotation medium prior to external loading thereof, said platform top surface having a width and a length, said post-tensioning means further interconnecting said portion of float units in side to side relation for providing an arched portion along at least a predetermined portion of both said platform top surface width and its length in said top surface configuration in said flotation medium prior to external loading of said platform.

13. A floating platform in accordance with claim 11 wherein each of said side wall portions includes at least one transverse tension element receiving passageway therein, each of said passageways being transversely axially aligned and opening on said opposed sides of said units at a level below said float unit top surface portion but in the upper portion of the plane of said side wall portion; each of said end wall portion includes at least one longitudinal tension element receiving passageway therein, each of said passageways being longitudinally axially aligned and opening on said opposed ends of said units at a level below said float unit top surface portion but in the upper portion of the plane of said end wall portion, said transverse and said longitudinal passageways being out of communication with each other; and said side to side and end to end interconnection means includes tension element means extending through said respective transversely and longitudinally axially aligned passageways.

14. A floating platform in accordance with claim 13 wherein said side to side and said end to end interconnection means further includes means for maintaining a predetermined tension on each of said respective tension element means for holding said float units together with a predetermined degree of pressure contact therebetween.

15. A floating platform comprising: a plurality of float units, each of said units having at least a substantially planar top surface portion and a pair of substantially upright opposed end wall portions; and posttensioning means for interconnecting said plurality of float units together in end to end relation with said substantially planar top surface portions being substantially flush with each other, said post-tensioning means extending substantially continuously through said plurality of float units and including means for maintaining a predetermined tension for said post-tension-ing means for holding said float units together with a predetermined degree of pressure contact therebetween, said platform having a top surface, said platform top surface having a configuration comprising said interconnected plurality of float unit top surface portions, each of said interconnected units having a predetermined mass upon which a buoyancy associated with a floatation medium for said units is sufficient to float said platform in said floatation medium, at least two of said float units having a different relative predetermined mass with respect to each other and the floatation medium prior to external loading thereof, the relative predetermined masses of said units being provided in accordance with the size of the unit, the relative mass varying in accordance with variations in unit size, said post-tensioning means interconnecting said plurality of float units together with said pressure contact therebetween, at least said two interconnected float unit top surface portions providing an arched portion in said floatation medium, said arched portion being along at least a predetermined portion of said platform top surface prior to external loading thereof. 

1. A floating platform comprising: a plurality of float units, each of said units having at least a substantially planar top surface portion and a pair of substantially upright opposed end wall portions; and post-tensioning means for interconnecting said plurality of float units together in end to end relation with said substantially planar top surface portions being substantially flush with each other, said post-tensioning means extending substantially continuously through said plurality of float units and including means for maintaining a predetermined tension for said post-tensioning means for holding said float units together with a predetermined degree of pressure contact therebetween, said platform having a top surface, said platform top surface having a configuration comprising said interconnected plurality of float unit top surface portions, each of said interconnected units having a predetermined mass upon which a buoyancy associated with a floatation medium for said units is sufficient to float said platform in said floating medium, at least two of said float units having a different relative predetermined mass with respect to each other and the floatation medium prior to external loading thereof, said post-tensioning means interconnecting said plurality of float units together with said pressure contact therebetween, at least said two interconnected float unit top surface portions providing an arched portion in said platform top surface configuration for said platform in said floatation medium, said arched portion being along at least a predetermined portion of said platform top surface prior to external loading thereof.
 2. A floating platform in accordance with claim 1 wherein the mass of said interconnected units is sufficient to float at least a part of said arched portion of said platform above the surface of said flotation medium.
 3. A floating platform in accordance with claim 1 wherein said plurality of float units includes at least one other float unit having a predetermined mass prior to external loading thereof which is substantially the same as the predetermined mass of one of said two units, said post-tensioning means interconnecting said one other unit and said two units in a substantially symmetrical arrangement in accordance with the relative masses of said units, said one other unit and said two units providing a substantially symmetrical arched portion in said platform top surface configuration along at least a predetermined portion of said platform top surface prior to external loading thereof.
 4. A floating platform in accordance with claim 1 wherein each of said end wall portions includes at least one tension element receiving passageway therein, each of said passageways being axially aligned and opening on said opposed ends of said units at a level below said float unit top surface portion but in the upper portion of the plane of said end wall portion; and said post tensioning interconnection means includes tension element means extending through said axially aligned passageways.
 5. A floating platform in accordance with claim 4 wherein said tension maintaining means includes means for maintaining a predetermined tension on said tension element means for holding said float units together with said predetermined degree of pressure contact therebetween.
 6. A floating platform in accordance with claim 5 wherein a resilient compression pad is disposed on said end wall portion between adjacent float units, said pad having an aperture therethrough of slightly greater transverse cross-sectional area than the transverse cross-sectional area of said tension element means, said aperture being axially aligned with said end wall passageway opening, said tension element means extending through said aperture, said pad being longitudinally compressed to deform said pad and distribute the pressure contact load between adjacent units when a predetermined tension is maintained on said tension element means for holding said float units together with said predetermined degree of pressure contact therebetween.
 7. A floating platform in accordance with claim 5 wherein a resilient compression pad is disposed on an end wall portion of each of said float units, said pad having an aperture therethrough of slightly greater transverse cross-sectional area than the transverse cross-sectional area of said tension element means, said aperture being axially aligned with said end wall passageway opening, said tension element means extending through said aperture, said pad being longitudinally compressed to deform said pad and distribute the pressure contact load on the respective unit when a predetermined tension is maintained on said tension element means for holding said float units together with said predetermined degree of pressure contact therebetween.
 8. A floating platform in accordance with claim 1 wherein each of said units comprises a hollow concrete box having a thickened top wall capable of withstanding a predetermined external loading of said platform, and said end wall portions are each of non-uniform thickness, said end walls being thicker above flotation line Of said buoyant concrete box than below said line.
 9. A floating platform in accordance with claim 1 wherein each of said units comprises a hollow concrete box.
 10. A floating platform in accordance with claim 1 wherein each of said float units comprises a hollow box, the interior of at least one of said units containing a predetermined quantity of ballast therein for providing said predetermined mass for said unit, the mass varying in accordance with variations in quantity of ballast.
 11. A floating platform in accordance with claim 1 wherein each of said units further includes a pair of substantially upright opposed side wall portions, said post-tensioning interconnecting means including means for interconnecting at least a portion of said plurality of float units together in side to side relation and at least a portion of said plurality of float units together in end to end relation with said top surface portions being substantially flush with each other.
 12. A floating platform in accordance with claim 11 wherein at least two of said side to side interconnected units have a different relative predetermined mass with respect to each other and the flotation medium prior to external loading thereof, said platform top surface having a width and a length, said post-tensioning means further interconnecting said portion of float units in side to side relation for providing an arched portion along at least a predetermined portion of both said platform top surface width and its length in said top surface configuration in said flotation medium prior to external loading of said platform.
 13. A floating platform in accordance with claim 11 wherein each of said side wall portions includes at least one transverse tension element receiving passageway therein, each of said passageways being transversely axially aligned and opening on said opposed sides of said units at a level below said float unit top surface portion but in the upper portion of the plane of said side wall portion; each of said end wall portion includes at least one longitudinal tension element receiving passageway therein, each of said passageways being longitudinally axially aligned and opening on said opposed ends of said units at a level below said float unit top surface portion but in the upper portion of the plane of said end wall portion, said transverse and said longitudinal passageways being out of communication with each other; and said side to side and end to end interconnection means includes tension element means extending through said respective transversely and longitudinally axially aligned passageways.
 14. A floating platform in accordance with claim 13 wherein said side to side and said end to end interconnection means further includes means for maintaining a predetermined tension on each of said respective tension element means for holding said float units together with a predetermined degree of pressure contact therebetween.
 15. A floating platform comprising: a plurality of float units, each of said units having at least a substantially planar top surface portion and a pair of substantially upright opposed end wall portions; and post-tensioning means for interconnecting said plurality of float units together in end to end relation with said substantially planar top surface portions being substantially flush with each other, said post-tensioning means extending substantially continuously through said plurality of float units and including means for maintaining a predetermined tension for said post-tension-ing means for holding said float units together with a predetermined degree of pressure contact therebetween, said platform having a top surface, said platform top surface having a configuration comprising said interconnected plurality of float unit top surface portions, each of said interconnected units having a predetermined mass upon which a buoyancy associated with a floatation medium for said units is sufficient to float said platform in said floatation medium, at least two of saiD float units having a different relative predetermined mass with respect to each other and the floatation medium prior to external loading thereof, the relative predetermined masses of said units being provided in accordance with the size of the unit, the relative mass varying in accordance with variations in unit size, said post-tensioning means interconnecting said plurality of float units together with said pressure contact therebetween, at least said two interconnected float unit top surface portions providing an arched portion in said floatation medium, said arched portion being along at least a predetermined portion of said platform top surface prior to external loading thereof. 